Energy resources (advantages and disadvantages of renewable & alternative sources)

Energy resources (advantages and disadvantages of renewable & alternative sources)

1. Non-renewable resources

   • Resources that are limited in quantity e.g. coal, oil, natural gas

2. Renewable resources

   • Resources that can be used without being depleted
     • Solar power
       • Energy from the sun converted into electricity
       • Generating solar power: install solar panels on rooftops of buildings of houses
         • panels consist of dark-coloured, heat-absorbing semi conductor platess stored in glass-covered boxes
           • Example: Solar power is increasingly being used in United States of America. About 1.2 million buildings in the United States of America have solar heating systems. such systems use solar power to heat water. One of the world's largest solar power plants is in California, a state along the west coast of USA
       • In countries with abundant sunlight like Australia, more households use solar panels
       • Some households use both solar power and oil-generated electricity as it is difficult to store power. Thus, oil-generated electricity is used when there is no light or little sunlight such as at night or wintertime
       • Advantages:
         • Sun's energy is available for all to use. No single country controls its supply
         • Energy from the sun is abundant
         • Producing solar power does not emit greenhouse gases
       • Disadvantages:
         • 1. Cost of producing and storing solar energy is high. Installing solar panels cost thousands of dollars
         • 2. Energy supply from solar panels varies with intermittent cloud cover
         • 3. Ways must be found to store solar energy efficiently for use when there is little or no sunlight
     • Wind power
       • Wind power is used to produce electricity through wind turbines
       • A group of wind turbines generating electricity in one location is known as a wind farm. A large wind farm can consist of hundreds of wind turbines
       • Advantages:
         • 1. Wind power is clean and renewable
         • 2. Land below wind turbines can still be used for other activities such as farming
         • 3. Wind turbines come in different sizes and can therefore be used by households, small businesses or industries
       • Disadvantages
         • 1. Energy supply from wind turbines varies as wind does not blow constantly all the time
         • 2.Wind turbines may cause noise pollution
         • 3. Wind turbines may affect wildlife.
         • 4. Some people may find the massive spinning blades of wind turbines unsightly and think that they spoil the natural scenery
       • Example: Denmark and Germany generate up to 20% of their electricity through wind turbines. Denmark aims to obtain 100% of its electricity from wind power by 2050
     • Hydropower
       • Hydropower uses the energy of fast running water to produce electricity.
       • A dam is built to control the flow of water by holding the water back in a reservoir and releasing the water as and when energy is needed. This produces an even flow of water throughout the year
       • Example: The Three Gorges Dam in China is the world's largest hydropower station and was completed in 2008
       • Advantages:
         • 1. Hydropower does not pollute the environment
         • 2. The cost of maintaining and operating a dam is relatively low
         • 3. The water contained in reservoirs by dams can be used for other purposes especially during dry seasons
       • Disadvantages:
         • 1. A dam disrupts the natural flow of water and disrupts the ecosystem
         • 2. Building a dam is restricted to suitable sites
         • 3. Over time, dams work less well as the reservoir fills up with sand and mud which reduces the capacity of the reservoir to store water
         • 4. As water is required to operate a dam, the energy output would be affected during a drought
         • 5. Much of the land upstream behind the dam will be flooded and people would have to relocate

3. Alternative sources

   • Energy resources that are alternative to fossil fuels
     • Nuclear energy
       • Produced by the splitting or fission of uranium atoms
         • Break apart easily as they have so many neutrons
         • When the nucleus of a uranium atom is split apart in a nuclear reactor, a large amount of heat energy is produced. The heat produced is then used to generate electricity
       • Example: In France, more than 75% of the country's electricity is generated from nuclear energy, making it the country's primary source of electricity
       • Advantage:
         • 1. One nuclear plant can generate a million times more electrical energy than hydropower or wind power
         • 2, Fewer raw materials are needed compared to a coal-fired station. In addition, uranium costs less than fossil fuels
           • 3. Electricity generated from nuclear energy is cheaper than electricity generated from fossil fuels
       • Disadvantage:
         • 1. Nuclear waste can remain radioactive for years and there are difficulties in reprocessing and storing nuclear waste. Leakages of radioactive waste from nuclear plants may pose a threat to the environment
         • 2. Building nuclear power plants can be costly and each plant may take as long as 20 years to build. The cost of shutting down old power station is extremely high
         • 3. Nuclear energy is not renewable. The uranium deposits on earth can only last for a limited amount of time